At present, a convergence network mainly consists of data convergence switches. However, it is easy to generate a layer-2 switching loop in the convergence network when the data convergence switches are used at present. For example, FIG. 1 shows a switching loop generated by three data convergence switches in a convergence network.
In order to solve the problem of layer-2 switching loop in the convergence network, network redundant links are selected and blocked mainly according to parameters like link costs of links, through layer-2 protocols such as Spanning Tree Protocol (STP) and Ethernet Automatic Protection Switching (EAPS), so that the links are disconnected.
After the links are disconnected by the above way, the disconnected links are still connected physically. The disconnected links cannot transmit service data but still can transmit protocol messages.
In existing protocols, link cost is determined by the transmission efficiency of the link, while the transmission efficiency of the link is only determined by the type of the link. Common link types mainly include optic fibre transmission and cable transmission; once a convergence network is established, the type of the link between every two data convergence switches is fixed; once the type of the link is fixed, the initial transmission efficiency of the link can be determined; and once the initial transmission efficiency of the link is fixed, the link cost of the link can be determined. Generally, the transmission efficiency of a link is in inverse proportion to the link cost of the link, for example, for a link with the initial transmission efficiency of 10M, the initial link cost of the link is 2000000; for a link with the initial transmission efficiency of 100M, the initial link cost of the link is 200000; for a link with the initial transmission efficiency of 1000M, the initial link cost of the link is 20000.
In order to solve the problem of layer-2 switching loop in the convergence network, generally layer-2 protocols such as STP and EAPS can be adopted to disconnect the link having a worse initial link cost (that is, the link with a lower initial transmission efficiency) in the switching loop according to the initial link cost of the link, so as to select the link having the minimum initial link cost (that is, the link with a higher initial transmission efficiency) in the switching loop as the main link.
However, in the above scheme of redundant link blocking (disconnecting), when a switching loop is selected, only the link type (that is, the corresponding initial link cost) of the link, rather than the dynamic change of the link cost of the link is taken into account, therefore, the link with a smaller initial link cost but actually having a low transmission efficiency may probably be selected as the main link, and other links with a relatively bigger initial link cost but actually having a better transmission efficiency are disconnected and in a blocked state, thus affecting the efficiency and reliability of service transmission in the convergence network.
Similarly, in other layers in the switching loop, similar problems may also appear.
In view of the problem in related art that the transmission efficiency and reliability of the convergence network are impacted by reason of determining the link actually having a worse link cost as the main link when a switching loop is blocked, no effective solution has been proposed so far.